Isolation apparatus and isolation methods

ABSTRACT

There is described an apparatus ( 14 ) for isolating a well bore ( 12 ). The apparatus ( 14 ) includes a sealing element ( 20 ) which is axially and transversely moveable relative to a sealing element seat ( 21 ). An actuator ( 30 ) is provided to axially and/or transversely move the sealing element ( 20 ) into sealing engagement with the sealing element seat ( 21 ) so as to isolate the well bore ( 12 ).

FIELD

The present disclosure relates to isolation apparatus and associated methods for isolation.

BACKGROUND

During operations in oil and gas wells there is a need to maintain control of the well pressure. In addition, a well operator may need to use equipment for accessing the well while ensuring that the well pressure remains under control. The well operator may utilise any appropriate equipment for accessing the well such as wire, pipe, slickline, braided cable, composite cable, micro-coil, coiled tubing, drilling and workover assemblies.

Typically, a set of pressure control equipment is used for controlling the well pressure. Typical well pressures being controlled can vary between 0 to 207 MPa (0 to 30,000 psi). Such pressure control equipment may need to be compatible with the equipment used for accessing the well. A blow-out preventer (BOP) may be provided at the top of a well and can be used to isolate a well in an emergency situation where well fluid pressure is excessive or unstable. The BOP provides a sealing function which can be activated in order to isolate the well when required. The BOP may comprise transversely (e.g. horizontal to the well bore) moveable rams that can be operated to close off and isolate the well as required. The BOP may further provide surface access or control of the well while the sealing function has been activated. The BOP may also cut or sever any portion of equipment that is disposed in the BOP while equipment is deployed downhole, thereby ensuring that the well has been isolated. A cutting element for severing the equipment may be provided separately to, or as part of, the BOP. In some examples, the transversely moveable rams may comprise the cutting element.

In normal (e.g. non-emergency) circumstances, there may be a need to exercise control over well pressure, or at least to isolate the well from the surface. Therefore, an isolation valve can be used to isolate the well as required, for example, where a bottomhole assembly is retrieved to surface and needs to be accessed. In some cases a dedicated isolation valve may be required to be installed during operations.

In general, a well head may include all three of a BOP, cutting valve and isolation valve as separate apparatus providing separate functionality at the well head.

SUMMARY

According to an example there is provided apparatus for isolating a well bore. The apparatus may comprise a sealing element moveable between a first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore and a second position in which the sealing element is axially and transversely displaced from the first position. The apparatus may comprise an actuator for moving the sealing element between the first and second positions.

In use, the apparatus may isolate the bore in order to isolate the well bore as required, for example, either temporarily or permanently. The bore may be part of or connected to the well bore used to provide access to a subterranean formation, e.g. for downhole operations. The bore may be part of or define a part of the apparatus. The apparatus may be used to provide well bore pressure control, for example, to prevent, control or mitigate the effects of a blow-out event. By moving the sealing element between the first and second positions, an operator may selectively isolate the well bore (for example from the surface) or provide access downhole, respectively. The apparatus may provide a relatively compact apparatus for isolating the well bore (for example, to isolate the well bore during normal operation) and being configured as a blow-out preventer (for example, to isolate the well bore in abnormal operation such as before, during or after an uncontrolled well pressure event has occurred). Sealing engagement between the sealing element and sealing element seat may remove the need to have separate apparatus (i.e. an apparatus for isolating the well bore in normal circumstances and further apparatus for isolating the well bore in abnormal circumstances). Thus, the apparatus of the present disclosure may be relatively compact, may require reduced working height/length and/or may have reduced weight compared to providing separate apparatus. Further, the apparatus may be installed as a single apparatus rather than separate apparatus, thus saving time and/or cost.

The sealing element may be configured such that well pressure assists in isolating the well bore, for example, by virtue of well pressure being applied to the sealing element to increase the force between the sealing element and the sealing element seat, which may produce an enhanced or positive sealing effect between the sealing element and the sealing element seat. The sealing element may be axially moveable to the first position. The sealing element may be transversely moveable to the first position. Fluid pressure from the well may be applied axially on the sealing element to apply an axial force on the sealing element. Where the sealing element is in the first position, the axial force exerted on the sealing element may increase the force between the sealing element and the sealing element seat.

Moving the sealing element to the first position may seal the bore, thus isolating the well bore from surface. Moving the sealing element to the second position may unseal the bore, for example at least partially opening the bore, thus providing access to the well bore from surface.

If any equipment needs to be deployed downhole, the sealing element may be moved to the second position so as to open up the bore sufficiently to permit the access downhole. If the well bore needs to be isolated while the equipment is deployed downhole, the sealing element may be moved from the second position to the first position so as to provide the sealing element in sealing engagement with the sealing element seat.

Where equipment is deployed downhole, a portion of the equipment may be disposed in the bore, thus preventing the sealing element from moving to a position that would otherwise be possible if the portion of equipment was not disposed in the bore.

The first position may either be defined as the position of the sealing element when the sealing element isolates the well bore with or without the portion of equipment disposed in the bore. For example, where no equipment is disposed in the bore the first position of the sealing element may define a “blind sealing” configuration.

Where the portion of equipment is disposed in the bore, the sealing element may provide a seal with the portion of equipment in the bore, for example, the sealing element may be provided in sealing engagement with an outer surface of the portion of equipment. At the same time, the sealing element may be provided in sealing engagement with the sealing element seat. In this manner, the portion of the bore which would otherwise provide fluid communication between the surface and the well bore may be sealed, thus isolating the well bore. In this case, the portion of equipment may be prevented from moving in the bore, for example, by virtue of the pressure applied from the sealing element on the portion of equipment. When the well bore is isolated in this manner, downhole operations may still be carried out using the equipment deployed downhole. If the portion of equipment in the bore needs to be moved relative to the sealing element, the sealing element may be moved from the first position, for example to or towards the second portion, to release the portion of equipment.

The apparatus may be provided as part of or in series with a well head. When the sealing element is axially moveable, the actuator may axially move the sealing element into sealing engagement with the sealing element seat. When the sealing element is transversely moveable, the actuator may transversely move the sealing element into sealing engagement with the sealing element seat. In some examples, the sealing element may only be axially moved into sealing engagement with the sealing element seat. In some examples, the sealing element may only be transversely moved into sealing engagement with the sealing element seat. In some examples, the sealing element may be simultaneously axially and transversely moveable into sealing engagement with the sealing element seat.

The sealing element may be initially disposed in the second position such that the apparatus does not isolate the well bore. The sealing element may subsequently be moved such that the sealing element moves to the first position and isolates the well bore. Moving the sealing element to the first position may isolate the surface from downhole fluid pressure in order to permit certain downhole operations to be carried out. The sealing engagement of the sealing element and the sealing element seat may also have utility as an emergency well bore isolator, for example, to reduce the risk of an uncontrolled or poorly-controlled fluid pressure situation, for example, before or when a blow-out occurs. The apparatus may thus serve to provide well bore isolation in either non-emergency or emergency situations. Isolating the well bore to permit certain downhole operations to be carried out as well as reducing the risk of an uncontrolled fluid pressure situation utilising the same apparatus may reduce the amount of space (e.g. vertical space) required, and/or may reduce the weight required.

The sealing element may be configured to be inserted into an internal bore defined by the sealing element seat.

Inserting the sealing element into the internal bore defined by the sealing element seat may permit sealing engagement between the sealing element and the sealing element seat. The internal bore may comprise or define a portion of the sealing element seat. The internal bore defined by the sealing element seat may form part of or be connected to the bore within which the sealing element is axially and/or transversely moveable. The internal bore may be distinguishable from the bore within which the sealing element is axially moveable. The internal bore may be adjacent to or axially displaced from the bore within which the sealing element is axially and/or transversely moveable.

The sealing element may be shaped to correspond to the inner surface of the internal bore defined by the sealing element seat.

An outer surface of the sealing element may comprise a tapered portion. The outer surface may comprise a stepped portion. The outer surface may comprise a flat bottomed portion. Any appropriate shape may be used for the outer surface.

The sealing element may be shaped to fit at least partially in the internal bore defined by the sealing element seat. The outer surface of the sealing element may comprise a portion shaped to correspond with the shape of the inner surface of the internal bore defined by the sealing element seat. The sealing element may be shaped to provide sealing contact with the internal bore defined by the sealing element seat. The internal bore defined by the sealing element seat may comprise a tapered portion. The internal bore may comprise a frustoconical-shaped inner surface configured to receive the tapered portion of the sealing element.

The sealing element may comprise a recess on a surface of the sealing element.

The recess may be shaped to permit the sealing element to provide sealing engagement with correspondingly shaped equipment when, in use, the equipment is disposed in the internal bore.

The recess may extend axially along the sealing element. The recess may be provided on an inner surface of the sealing element. The inner surface may be defined as or comprise the surface of the sealing element which in use, faces or sealingly engages the equipment. Providing the recess may allow the sealing element to fit around correspondingly shaped equipment disposed in the internal bore. In use, downhole operations may be carried out by accessing the wellbore through the internal bore using the equipment. If well bore isolation is required, the equipment may interfere with or prevent the isolation of the well bore. Thus, providing the recess may permit the sealing element to fit around a portion of the outer surface of the equipment. Accordingly when, in use, the sealing element is disposed in the internal bore of the sealing element seat, an outer surface of the sealing element may be provided in sealing engagement with a portion of the inner surface of the internal bore. Similarly, the inner surface of the sealing element comprising or defining the recess may be provided in sealing engagement with a portion of the outer surface of the equipment. Transversely moving the sealing element may permit the sealing element to contact any equipment disposed in the bore in the vicinity of the sealing element. Axially moving the sealing element may permit the sealing element to move axially along the bore such that the sealing element may slide axially along or move adjacently to the equipment. The sealing element may surround the equipment such that when the sealing element engages the sealing element seat, the sealing element seals around the equipment. In some examples where the sealing element comprises a recess, the sealing element may or may not additionally be able to isolate the well bore where any equipment is not deployed downhole (i.e. even if no equipment is deployed, the sealing element comprising a recess may still be deployed to isolate the well bore).

An intermediate position may be defined between the first position and the second position. The intermediate position may be axially displaced from the first position. The intermediate position may be transversely displaced from the second position.

The sealing element may be axially moveable between the intermediate position and the first position. The sealing element may be transversely moveable between the intermediate position and the second position. When moving from the first position to the second position, the sealing element may be moved from the first position to the intermediate position, and then the sealing element may be moved from the intermediate position to the second position. When moving from the second position to the first position, the sealing element may be moved from the second position to the intermediate position, and then the sealing element may be moved from the intermediate position to the first position. By moving the sealing element between the first position and the intermediate position, the sealing element may be axially moveable in the internal bore. At the same time, transverse movement of the sealing element may be prevented. In some examples, the sealing element may be simultaneously axially and transversely moveable. By moving the sealing element between the intermediate position and the second position, the sealing element may be moved to provide access for equipment downhole.

The sealing element may be pivotable between the intermediate position and the second position.

The sealing element may, in use, be in the second position. When in the second position, the sealing element may be provided in a transverse orientation. The sealing element may be disposed in a side pocket adjacent the bore.

The sealing element may, in use, be in the first or intermediate position. When in the first or intermediate position, the sealing element may be provided in a longitudinal orientation. The sealing element may be disposed in the bore.

Moving the sealing element out of, for example radially out of, the bore may allow the bore to be substantially unobstructed by the sealing element, which may permit unimpeded access to the well bore and/or may permit fluid flow through the bore to be maximised. In some examples, the sealing element may remain partially disposed in the bore when in the second position, but may still provide the same or similar functionality as provided for when the sealing element is disposed out of the bore. Thus, providing the sealing element in the second position may provide for relatively unimpeded access to the well bore and/or increased fluid flow through the bore relative to when the sealing element is in the deployed configuration. Further, providing the sealing element in the first or intermediate position may isolate or partially isolate the bore, respectively. When partially isolated, flow through the bore may be restricted. Whether isolated or partially isolated, providing the sealing element in the first or intermediate position may allow for containment of relatively higher pressure downhole, and/or may allow for depressurisation at the surface.

The actuator may comprise at least one sleeve for moving the sealing element between the first and second positions.

The actuator may comprise concentric sleeves configured for moving the sealing element.

A first sleeve may be axially moveable between a deploy position in which the first sleeve provides the sealing element in one of the first and intermediate positions, and a retract position in which the first sleeve provides the sealing element in the second position.

A second sleeve may be axially moveable between a sealing element unsealed position in which the sealing element is provided in the second position and in fluid communication with the well bore, and a sealing element sealed position in which the sealing element is in the second position and isolated from the well bore.

The first sleeve may comprise or define an outer sleeve. The second sleeve may comprise or define an inner sleeve. In some examples the first sleeve may comprise or define the inner sleeve and the second sleeve may comprise or define the outer sleeve. The first sleeve may extend axially beyond the second sleeve. The second sleeve may extend axially beyond the first sleeve. The apparatus may comprise a third or further sleeves. The moveable sleeve arrangement may provide a relatively compact arrangement for well bore isolation and/or blow-out prevention. The apparatus may have a relatively low height/length and or may be relative lightweight. Additionally, providing axially moveable sleeves may provide a reduced footprint for the apparatus, thus permitting installation of the apparatus in tighter spaces (e.g. where there is sufficient axial space but insufficient transverse space). The apparatus may thus be considered to be relatively compact. Providing the axially moveable sleeve arrangement may provide a reduced footprint by virtue of the sealing element being axially moveable. Were the sealing element to be only transversely moveable, this may result in an apparatus having a larger footprint.

The apparatus may comprise a retract chamber provided between the first sleeve and a housing for the first and second sleeves. The retract chamber may be fillable with fluid, for example, so as to apply or permit application of fluid pressure on a first sleeve piston element provided on the first sleeve.

The apparatus may comprise a deploy chamber provided between the second sleeve and the housing. The deploy chamber may be fillable with fluid so as to apply or permit application of fluid pressure on the first sleeve piston element provided on the first sleeve and a second sleeve piston element provided on the second sleeve.

The apparatus may comprise a well isolation chamber provided between the second sleeve and the housing. The well isolation chamber may be fillable with fluid so as to apply or permit application of fluid pressure on the second sleeve piston element.

The housing may surround the first and second sleeves. The first and second sleeves may each be independently moveable relative to each other and to the housing. The first and second sleeves may be dependently moveable relative to each other, for example, when a fluid or fluid pressure is locked in at least one of the retract, deploy and pocket isolation chambers.

The retract chamber, the deploy chamber and/or the well isolation chamber may be arcuate or annular in form. At least one fluid port may be provided in the housing to provide fluid communication with the respective chamber. In use, fluid may be pumped into or withdrawn from at least one of the chambers to move the sealing element between the first, intermediate and second positions. Pressure on the piston element may apply an axial force on the respective sleeve, thereby resulting in movement of the sleeve. Selecting a fluid pressure in at least one of the chambers may provide appropriate movement the respective sleeve so as to, for example, appropriately move the sealing element. The actuator may be configured to axially move the sealing element in the bore, for example, into or out of sealing engagement with the sealing element seat. Fluid pressure in at least one chamber may maintain the sealing element in either the first, second or intermediate positions. While the sealing element is maintained in either the first, second or intermediate positions, fluid pressure in another of the chambers may be varied so as to move the sealing element in an axial and/or transverse direction. By appropriately adjusting the volume of fluid and/or fluid pressure in each of the retract, deploy and well isolation chambers, an operator may selectively provide the sealing element in the first, second or intermediate positions, and/or move the sealing element between these positions.

The pocket isolation sleeve may isolate the side pocket from the well bore. In use, the side pocket may be configured to accommodate the sealing element when the sealing element is in the second position.

Fluid pressure in the bore may be maintained (or may be increased by closing a nearby valve or isolation device) so as ensure a positive pressure difference is maintained between well bore and the side pocket (and thus may assist in isolating the side pocket from the well bore). Once the side pocket is isolated from the bore, fluid may be drained or bled from the side pocket so as to permit safe access to the side pocket. Pressure between the side pocket and the exterior of the side pocket may be equalised to provide access to the side pocket. An operator may then check, service, install, remove or replace components in the side pocket. Providing access to the side pocket while the bore is pressurised may allow for the sealing element to be replaced if damaged without interfering with downhole operations. In addition or alternatively, the operator may wish to deploy different equipment downhole (or perhaps equipment is no longer required). The currently installed sealing element may not comprise a recess or may comprise an inappropriately shaped recess and thus may be unsuitable for the new equipment (or may be unsuitable if no equipment is required). Accordingly, the operator may safely isolate the sealing element in the side pocket and change for a new sealing element that may be suitable for use with the new equipment (if required). This ability to readily change the sealing element may provide greater flexibility and/or decrease time spent in terms of how quickly different equipment can be deployed. Also, space, money and/or time may be saved if the same apparatus can be used to isolate the well bore irrespective of whether any equipment (e.g. of any size/kind) is intended to be deployed downhole. The sealing element may thus be safely checked, serviced, installed or replaced while the well bore is under pressure. Providing access to the sealing element via the depressurised side pocket may provide the ability to change the sealing element while the well bore is pressurised, which may not otherwise be possible.

The apparatus may comprise a plurality of sealing elements.

The collective shape defined by the sealing elements, when the sealing elements are in the first or intermediate positions, may define a shape which may be suitable for providing sealing engagement with the sealing element seat. For example, the collective shape may be shaped to correspond to the internal bore of the sealing element seat. In some examples, two sealing elements may be provided on either side of the bore. The two sealing elements may collectively substantially define a frustocone, or other appropriate shape, adapted to be sealingly engaged with the sealing element seat. Each sealing element or at least one of the sealing elements may comprise the recess. The sealing element or sealing elements may collectively surround the portion of equipment, if deployed downhole. Providing more than one sealing element may allow for simpler and more reliable sealing around the equipment, for example, because a perimeter of the equipment can be completely or substantially surrounded by an inner surface of the collective sealing elements. In some examples, the apparatus may only comprise one sealing element. In such examples, the sealing element may be configured to completely or substantially surround the portion of equipment.

Where more than one sealing element is provided, each sealing element may be independently moveable with respect to the other sealing elements. Thus, each sealing element may be deployed at different times or rates. In this manner, each sealing elements may be moved without affecting or disrupting the movement or operation of the other sealing elements.

Each sealing element may be associated with a side pocket. Each sealing element may provide the same or similar functionality as the sealing element described herein.

The apparatus may comprise a guide for locating the sealing element with respect to a portion of equipment when, in use, the equipment is disposed in the bore.

The guide may help to ensure any equipment disposed in the bore is correctly located with respect to the sealing element. In some examples, the guide may act to direct the sealing element towards the portion of equipment such that the portion of equipment is locatable in the recess. In some examples, the guide may comprise or be in the form of a wire of any appropriate shape, for example a V-shaped wire (the equipment may be locatable within the V). In some examples, no guide may be required. In some examples, a guide may be provided on at least one of the sealing elements. The guide may be disposed on or adjacent a lower portion of the sealing element. When the sealing element is moved to the intermediate position from the second position, the lower portion of the sealing element may be initially closest to the equipment. Accordingly, providing the guide on or adjacent the lower portion may allow the sealing element to be correctly located with respect to the equipment before the sealing element has been fully deployed.

The sealing element may comprise any appropriate material. The sealing element may have any appropriate property to provide for sealing engagement with the sealing element seat. For example, such properties may comprise at least one of elasticity, plasticity, deformability, durability, and the like.

In a further example there is provided apparatus for isolating a bore, comprising: a sealing element moveable between a first position in which the sealing element is in sealing engagement with a sealing element seat disposed in the bore and a second position in which the sealing element is axially and transversely displaced from the first position. The apparatus may comprise an actuator for moving the sealing element between the first and second positions. The apparatus may have utility in isolating any type of bore, for example, including but not limited to a well bore. Features and optional features associated with the apparatus for isolating a well bore described herein may be equally usable in connection with the apparatus for isolating any type of bore.

According to a further example there is provided apparatus for isolating a well bore. The apparatus may comprise a well bore isolation device. The well bore isolation device may comprise a moveable isolation element. The moveable isolation element may comprise a sealing element seat. In a first isolation device position, the sealing element seat may be axially aligned with a bore. The sealing element seat may be configured to be sealingly engaged by a sealing element. The sealing element may be provided in accordance with any sealing element provided in any example described herein. In a second isolation device position, the moveable isolation element may be moved out of axial alignment with the bore.

In use, the well bore isolation device may be complementary to the sealing element described herein. Accordingly, features associated with the apparatus comprising the sealing element may be appropriately associated or combined with features associated with the well bore isolation device. A sealing element may be sealingly engaged with the sealing element seat of the well bore isolation device. In the first isolation device position the sealing element seat may provide access from surface to downhole via the apparatus. Accordingly, if temporary or non-emergency well bore isolation is required, the sealing element and the sealing element seat may be sealingly engaged together as described herein. However, if emergency pressure control is required, the moveable isolation element may be moved to isolate the well bore. Moving the moveable isolation element may misalign the sealing element seat from a bore adjacent the moveable isolation element. Moving the moveable isolation element may move the sealing element seat out of communication with the fluid in the well bore. Thus, the apparatus may provide the function of a blow-out preventer. The apparatus according to this third example may be provided in its own right without needing to be sealingly engaged by the sealing element described herein. For example, the well bore isolation element may simply be used to provide emergency pressure control and may not necessarily be used provide temporary or non-emergency well bore isolation.

The apparatus may provide a relatively compact apparatus for isolating the well bore (for example, to isolate the well bore during normal operation) and may be configured as a blow-out preventer (for example, to isolate the well bore in abnormal operation such as before, during or after an uncontrolled well pressure event has occurred). Sealing engagement between the sealing element and sealing element seat may remove the need to have separate apparatus (i.e. an apparatus for isolating the well bore in normal circumstances and further apparatus for isolating the well bore in abnormal circumstances). Thus, the apparatus of the present disclosure may be relatively compact, may require reduced working height/length and/or may have reduced weight and/or may provide a reduced footprint compared to providing separate apparatus.

The moveable isolation element may comprise an internal bore shaped to correspond to an outer surface of the sealing element. The sealing element seat may comprise or define an entrance of the internal bore. The internal bore may comprise a tapered portion. The internal bore may comprise a stepped portion. The internal bore may comprise a flat bottomed portion. Any appropriate shape may be used for any portion of the internal bore.

The internal bore may be shaped so as to permit, in use, the sealing element to be sealingly engaged with the sealing element seat. The internal bore may be shaped so as to permit the forming of a corresponding fit with the sealing element. The internal bore may comprise a frustoconical-shaped inner surface configured to receive a tapered portion of the sealing element.

The apparatus may comprise a cutting element for severing a portion of equipment disposed in the well bore isolation device.

The apparatus may be configured to sever or at least partially sever any equipment disposed in the well bore isolation device. Movement of the moveable isolation element may sever the equipment disposed in the well bore isolation device. In use, the sealing element may or may not be disposed in the well bore isolation device when the apparatus is actuated to sever the equipment. The cutting element may comprise or be defined by a cutting edge of the moveable isolation element. For example, the cutting edge may comprise an axial end edge of the internal bore. The cutting element may comprise or be defined by a cutting edge of a well isolation body housing the moveable isolation bore. For example, the cutting edge may comprise an internal edge of the well isolation body.

The apparatus may provide a relatively compact apparatus for isolating the well bore (for example, to isolate the well bore during normal operation) and being configured as a blow-out preventer (for example, to isolate the well bore in abnormal operation such as before, during or after an uncontrolled well pressure event has occurred). Providing the cutting element within the same apparatus may provide a relatively compact well bore isolation apparatus, instead of having to provide separate apparatus for well bore isolation, blow-out prevention and cutting. Thus, the apparatus may have relatively reduced height/length and/or may be reduced in weight and/or may have a reduced footprint compared to providing separate apparatus. Time and/or costs may be saved by installing the apparatus as a single entity, rather than separately installing separate equipment.

The moveable isolation element may comprise a rotatable ball.

The rotatable ball may comprise cutting edges. When, in use, the rotatable ball is rotated in the well isolation body from the first isolation device position to the second isolation device position, the cutting edges may be moved to close the well bore. In some examples, the well isolation device may comprise a gate valve. The apparatus may comprise a plurality of moveable isolation elements, for example, a plurality of rotatable balls provided in series. Providing a plurality of moveable isolation elements may provide back-up in case of failure of at least one of the other moveable isolation elements, thus increasing the safety margin.

According to a further example there is provided an assembly for isolating a well bore. The assembly may comprise apparatus comprising a sealing element according to any example described herein. The assembly may comprise apparatus comprising a well bore isolation device according to any example described herein.

The assembly may provide a relatively compact isolation apparatus with the ability to either isolate the well bore in emergency or non-emergency situations, and may also be capable of severing any equipment disposed in the internal bore. The integrated functionality of the apparatus comprising the sealing element and the apparatus comprising the moveable isolation element may provide a simpler, more compact, lower height and/or lower weight assembly without the need for separate or individual tools to provide the same functionality. The assembly may be provided as a single entity. Time and/or costs may be saved by installing the assembly as a single entity, rather than separately installing separate equipment.

The assembly may comprise a side pocket adapted to accommodate the sealing element. The assembly may comprise a housing comprising the side pocket. The assembly may comprise a housing defining the bore within which the sealing element is axially and/or transversely movable. The assembly may provide an integrated approach to isolating the well bore in different situations, for example, the ability to change the sealing element while the well bore is pressurised may save time and may permit efficient operation of the well when different equipment are to be deployed downhole.

According to a further example there is provided a method of unsealing a well bore. The method may comprise providing a sealing element in a first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore. The method may comprise moving the sealing element axially and transversely to a second position in which the sealing element is axially and transversely displaced from the first position.

According to a further example there is provided a method of isolating a well bore. The method may comprise providing a sealing element in a second position in which the sealing element is axially and transversely displaced from a first position. The method may comprise moving the sealing element to the first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore.

The methods may comprise moving the sealing element from the first to the second position to unseal the well bore. The methods may comprise moving the sealing element from the second to the first position to isolate the well bore. Thus, an operator may move the sealing element according to whether the well bore needs to be isolated or unsealed.

The method may comprise moving the sealing element to the first position by inserting the sealing element in an internal bore defined by the sealing element seat. The sealing element seat may comprise or define an entrance to the internal bore. The sealing element may be shaped to correspond to the shape of the sealing element seat. The correspondingly shaped sealing element and sealing element seat may permit sealing engagement to be achieved when the sealing element is provided in the first position.

The method may comprise moving the sealing element between the second position in which the sealing element is axially and transversely displaced from the first position and transversely moving the sealing element to an intermediate position in which the sealing element is axially displaced from the first position.

The method may comprise transversely moving the sealing element from the intermediate position to the second position.

The method may comprise axially moving the sealing element from the intermediate position to the first position.

The method may comprise axially moving the sealing element from the first position to the second position.

The sealing element may be moved from the first position to the second position via the intermediate position. The sealing element may be moved from the second position to the first position via the intermediate position.

The method may comprise providing the sealing element in the second position within a side pocket adjacent the bore. The method may comprise isolating the side pocket from the bore. The method may comprise accessing the sealing element in the side pocket for at least one of: inspection, repair, installation, removal and replacement of the sealing element. The method may comprise depressurising the side pocket to permit access to the sealing element in the side pocket. The method may comprise equalising the pressure between the side pocket and the exterior of the side pocket. The method may comprise providing a plurality of sealing elements.

According to a further example there is provided a method of isolating a well bore. The method may comprise providing a well bore isolation device comprising a moveable isolation element. The moveable isolation element may comprise a sealing element seat for providing fluid communication with the well bore. The method may comprise providing the well bore isolation device in a first well isolation device position in which the sealing element seat is in fluid communication with the well bore. The sealing element seat may be adapted to be sealingly engaged by a sealing element in accordance with any example of a sealing element described herein. The method may comprise moving the well bore isolation device to a second well isolation device position by moving the well bore isolation device to prevent fluid communication with the well bore.

The moveable isolation element may comprise an internal bore shaped to correspond to an outer surface of the sealing element. The sealing element seat may comprise or define an entrance of the internal bore. The internal bore may comprise a tapered portion shaped to correspond to a portion of the outer surface of the sealing element seat.

The method may comprise moving the sealing element from the sealing element seat to unseal the well bore before the well bore isolation device is moved to the second well isolation device position.

The method may comprise providing the sealing element in sealing engagement with the sealing element seat such that the sealing element remains sealingly engaged with the sealing element seat. The method may comprise moving the well bore isolation device to the second well isolation device position.

The method may comprise severing a portion of equipment disposed in the well bore isolation device.

The well bore isolation device may comprise a cutting element configurable to sever the portion of equipment. If the sealing element is in sealing engagement with the sealing element seat, the cutting element may move to sever the sealing element and/or the portion of equipment. Using the well bore isolation device to sever the equipment and/or the sealing element may allow the well bore to be isolated in emergency situations, for example, where there is insufficient time to retract the sealing element. The method may thus provide the function of a blow-out preventer.

According to a further example there is provided a method of isolating a well bore. The method may comprise any method comprising moving a sealing element in accordance with any example described herein. The method may comprise any method comprising moving a well bore isolation device in accordance with any example described herein.

The present disclosure may include one or more corresponding aspects, embodiments, examples or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, features associated with particular examples relating to apparatus, assemblies or products may be equally appropriate as features of examples relating to methods or processes, and the like.

The above summary is intended to be merely exemplary and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1a is a cross-sectional view of an example of a well bore sealing apparatus in a retracted unsealed configuration;

FIG. 1b is a side view of the apparatus illustrated in the retracted unsealed configuration of FIG. 1 a;

FIG. 2 is a cross-sectional view of the well bore sealing apparatus in a deployed unsealed configuration;

FIG. 3 is an enlarged cross-sectional view of the well bore sealing apparatus illustrated in FIG. 2;

FIG. 4 is a cross-sectional view of the well bore sealing apparatus in a retracted sealed configuration; and

FIG. 5 is a cross-sectional view of the well bore sealing apparatus in a deployed sealed configuration.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an assembly 10 for isolating a well bore 12. The assembly 10 is typically located at a well head of the well bore 12, but may be deployed in any appropriate location. Only one side of the assembly 10 is shown in the interests of clarity. Accordingly, any reference to a single feature in the description that follows may be referring to a plurality of these features. In the examples that follow, the assembly 10 includes corresponding apparatus on both sides of the well bore 12 such that the apparatus on one side of the assembly 10 substantially mirrors the apparatus on the other side of the assembly 10. In the interests of clarity the description refers to a single feature where a single feature is illustrated in the figures, however it will become apparent that in some cases there may actually be a plurality of these features (even though these are not explicitly illustrated in the figures). This will explained further herein. It will also become apparent that other configurations are possible, for example, two, three, four, or more corresponding apparatus may be circumferentially spaced around the well bore 12.

Terms such as transverse, horizontal, longitudinal, axial, vertical, upper, lower are used throughout this disclosure and a person of ordinary skill in the art would understand that these terms are merely relative to the well bore 12 (e.g. the well bore 12 axis). Unless specific otherwise, these terms are relative to the axial direction of the well bore 12 (e.g. the terms “longitudinal” and “vertical” would be understood as being parallel to the axial direction of the well bore 12 and the terms “transverse” and “horizontal” would be understood as being perpendicular to the axial direction of the well bore 12). Terms such as “upper” generally refer to a direction towards the surface whereas “lower” generally refer to a direction downhole, however if any part of the assembly 10 is inverted in the well bore 12 the person of ordinary skill in the art would properly understand the context of such terms.

The assembly 10 includes an axially moveable sealing apparatus 14 (in this example, two apparatus 14 provided on opposing sides of the well bore 12, although only one apparatus 14 is shown in the interests of clarity) and a sealing device 16. The two apparatus 14 may operate using slightly different timing, depending on the particular configuration of the assembly 10. As is explained in further detail herein, in use, the sealing apparatus 14 engages the sealing device 16 to isolate the well bore when required. When isolation is no longer required, the sealing apparatus 14 and sealing device 16 are disengaged. The assembly 10 includes a side pocket 18 (e.g. one for each sealing apparatus 14) extending radially outwardly (e.g. transversely) of the well bore 12 for housing a sealing element 20 (e.g. one sealing element 20 on each side of the assembly 10) of the apparatus 14 when sealing is not required. In examples where there are two or more sealing elements 20 (in the present example there are two sealing elements 20), the sealing elements 20 may be equally distributed circumferentially around the assembly 10 and it will be appreciated that corresponding features (e.g. a side pocket 18 for each sealing element 20) of the assembly 10 may accompany these sealing elements 20. As already mentioned, the sealing apparatus 14 may operate using slightly different time. Thus, it will be appreciated that the particular timing for deploying the sealing elements 20 may or may not depend on the particular configuration of the assembly 10. For example, individual sealing elements 20 may or may not be moved to engage or disengage the sealing device 16 at different times. Thus, the sealing elements 20 may or may not be operated independently on each other. In this manner, independently operating each sealing element 20 may prevent the sealing element 20 from affecting or disrupting other sealing elements 20.

In order to isolate the well bore 12, the sealing element 20 may be moved into sealing engagement with the sealing device 16. The sealing device 16 includes a sealing element seat 21. In the present example the sealing device 16 includes the sealing element seat 21 and provides additional functionality as described herein. However, in some examples there may only be a sealing element seat 21 disposed in the vicinity of the sealing apparatus 14. In some examples, the sealing element seat 21 may be disposed in a bore or may define a bore entrance. Sealing engagement between the sealing element 20 and the sealing element seat 21 may isolate the well bore 12. In use, the sealing element 20 is moveable to a first position (as illustrated by FIG. 5) in which the sealing element 20 sealingly engages the sealing element seat 21. The sealing element 20 is moveable to a second position (for example, as illustrated by FIGS. 1a and 4) in which the sealing element 20 is no longer in sealing engagement with the sealing element seat 21. In FIGS. 1a and 4, the sealing element 20 is axially and transversely displaced from the first position illustrated by FIG. 5. In FIG. 2, the sealing element 20 is axially displaced from the first position but is not transversely displaced. The sealing element 20 may thus be considered as being in an intermediate position. From the intermediate position, the sealing element 20 may subsequently be transversely moved (i.e. in a radial (e.g. transverse) direction away from the well bore 12 axis) towards the second position or may subsequently be axially moved to the first position. The sealing element 20 is moveable between the first, second, intermediate and further positions as and when required.

The sealing apparatus 14 can be provided in one of several configurations. The configuration shown in FIGS. 1a and 1b is an unsealed second position in which the sealing element 20 is retracted in the second (e.g. horizontal) position (i.e. relative to the well bore 12 axis (A)) and is located in the side pocket 18 which is in fluid communication with the well bore 12. The sealing element 20 may or may not be axially moveable within the confines of the side pocket 18 while in the second position. In the unsealed second position of FIGS. 1a and 1b , the sealing apparatus 14 is positioned such that, if required, the sealing element 20 can be pivoted via pivot 22 into a longitudinal (e.g. vertical) orientation (i.e. relative to the well bore 12 axis (A)). Due to the dimension confines of the side pocket 18, the distance between the pivot 22 point and an upper inner surface 24 of the side pocket 18 (when in the unsealed second position) is selected to allow the sealing element 20 to be pivoted towards and away from the longitudinal orientation without an edge of the sealing element 20 contacting the upper inner surface 24. In the second position, an inner surface portion 26 of the sealing element faces the upper inner surface 24. In the second position the sealing element 20 is located in a side pocket volume 28 so as to not obstruct the adjacent well bore 12.

Referring also to FIG. 2 (and FIG. 3 which shows an expanded view of the sealing element 20 of FIG. 2), the sealing apparatus 14 is shown in the intermediate position in which the sealing element 20 is provided in the longitudinal orientation, but axially displaced from the sealing element seat 21. Although not illustrated in the figures, a further sealing element 20 is provided on the opposite side of the well bore 12. In the intermediate position, both sealing elements 20 are provided in the longitudinal orientation shown in FIG. 2 such that the respective inner surface portions 26 of each sealing element 20 are facing each other (and may or may not be in contact with each other). The sealing elements 20 may provide support for each other in this configuration if the elements 20 are in facing contact. In the intermediate position the sealing elements 20 may not seal off the well bore 12 because the collective cross-sectional area (relative to the longitudinal axis of the sealing element 20) of the two sealing elements may be less than the cross-sectional area of the well bore 12 in the vicinity of the sealing elements 20 in the intermediate position. However, the well bore 12 may be substantially obstructed by the sealing elements 20 such that in some cases the fluid flow may be reduced and there may be a fluid pressure difference either side of the sealing elements 20.

The sealing apparatus 14 includes an actuator 30 to allow the sealing apparatus 14 to be moved in an axial direction between the intermediate position (as illustrated by FIGS. 2 and 3) and the first position (as illustrated by FIG. 5). The actuator 30 also allows the sealing element 20 to be pivoted between the unsealed second position (as illustrated by FIG. 1a ) and the intermediate position (as illustrated by FIGS. 2 and 3). When the sealing element 20 is in the intermediate position, the well bore 12 may not be isolated, or at least there may be substantially reduced fluid flow through the well bore 12. The actuator 30 also allows the sealing apparatus 14 to be configured between the unsealed side pocket 18 configuration (as illustrated by FIG. 1a ) and a sealed side pocket 18 configuration (as illustrated by FIG. 4). In both configurations the sealing element 20 remains in the second position. Further details of the operation of the actuator 30 are provided below.

The actuator 30 may take any appropriate form and may include an actuator for providing axial movement and an actuator for providing pivoting movement of the sealing element 20. An actuator 30 may be provided for each sealing element 20, or a single actuator 30 may be provided for all sealing elements 20 of the assembly 10.

In some examples the sealing elements 20 may have a planar inner surface portion 26 which may be used when no equipment is deployed downhole. In some examples the sealing elements 20 may have a recess 32 (as illustrated by FIG. 1b ) extending longitudinally along the inner surface portion 26. The recess 32 of each sealing element 20 is shaped to correspond to a portion of the external shape of any equipment (not shown) (e.g. slickline, braided cable, composite cable, micro-coil, coiled tubing, drilling and workover assemblies) deployed downhole via the assembly 10. The recess 32 allows the sealing element 20 to be provided in the longitudinal orientation when the equipment is deployed downhole. The sealing elements 20 having a recess 32, may or may not additionally be able to isolate the well bore 12 where any equipment is not deployed downhole.

Thus, the sealing elements 20 can collectively surround the portion of the equipment present in the vicinity of the sealing elements 20. In this example, a guide 34 in the form of a wire is provided at a base 36 of the sealing element 20. In other examples, a guide 34 may be provided at alternative locations, or may not even be required. The guide 34 guides the sealing element 20 towards the equipment (not shown) such that the equipment is guided into the recess 32 when the sealing element 20 is pivoted into the longitudinal orientation.

The configuration and operation of the actuator 30 is now explained in further detail. The actuator 30 moves the base 36 of the sealing element 20, the base 36 being pivotable about the pivot 22. The base 36 is mounted on a pivot housing 38, which houses the pivot 22. The pivot housing 38 includes a pivot housing lip 40 and a pivot housing shoulder 42.

The actuator 30 includes a deployment sleeve 44 provided between a pocket isolation sleeve 46 and a housing 48 of the assembly 10. The deployment sleeve 44 and pocket isolation sleeve 46 are axially moveable, and are each moveable relative to the assembly housing 48. The deployment sleeve 44 includes a deployment sleeve shoulder 50 at an upper portion of the deployment sleeve 44 and a deployment sleeve lip 52 at an uppermost portion of the deployment sleeve 44. The upper portion of the deployment sleeve 44 including the deployment sleeve shoulder 50 and deployment sleeve lip 52 radially extends into the entrance of the side pocket 18.

The base 36 includes a base lip 54 extending perpendicularly from the base 36. The base lip 54 is provided at or in the entrance of the side pocket 18. When the sealing apparatus 14 is required in the second position, the guide 34 and base 36 are pivoted out of the well bore 12 to be provided at or in the entrance of the side pocket 18. In this manner, the pocket isolation sleeve 46 can then be moved past the guide 34 and base 36 to close and seal/isolate the side pocket 18, as explained in further detail herein.

In order to provide the sealing apparatus 14 in the second position illustrated by FIGS. 1a, 1b and 4 (and as illustrated by the solid line relating to the upper portion of the deployment sleeve 44 in FIGS. 2 and 3), the deployment sleeve lip 52 is moved (downwardly in the present example) to a retract position 56 below the pivot 22 point such that the base 36 can be pivoted. The sealing element 20 can then be transversely moved towards the second position until the base lip 54 abuts or almost abuts the deployment sleeve lip 52. When the deployment sleeve lip 52 is moved to the retract position 56, the deployment sleeve lip 52 also abuts the pivot housing lip 40, thus preventing further downward movement of the deployment sleeve 44 relative to the base 36.

When the sealing apparatus 14 is in the second position illustrated in FIG. 1a , the deployment sleeve shoulder 50 abuts (or may abut) a lower inside surface 58 of the side pocket 18. A minimum distance may be defined between the pivot housing 38 and the lower inside surface 58 (for example using a shoulder arrangement (not shown)) in order to allow the deployment sleeve lip 52 to move below the pivot 22 point (thereby permitting the sealing element 20 to be pivoted to the second position).

When the well bore 12 is required to be isolated by the sealing apparatus 14, the sealing element 20 is pivoted to the longitudinal orientation by upward movement of the deployment sleeve 44 to provide the sealing apparatus 14 in the intermediate position (as is illustrated by FIG. 2). In this manner, the deployment sleeve lip 52 pushes upwardly against the base lip 54 so as to pivot the base 36 and sealing element 20 into the longitudinal orientation. To maintain or lock the sealing element 20 in the longitudinal orientation, the deployment sleeve lip 52 abuts a side of the base lip 54 to prevent pivoting of the sealing element 20 towards the second position. When maintaining or locking the sealing element 20 in the longitudinal orientation, the deployment sleeve lip 52 is provided in a deploy position 60 (see the dashed line relating to the upper portion of the deployment sleeve 42 in FIGS. 2 and 3). In addition, the deployment sleeve shoulder 50 abuts a lower surface of the pivot housing 38 to prevent further upward relative movement of the deployment sleeve 44.

In order to move the deployment sleeve 44 so as to retract the sealing apparatus 14, there is provided a retract port 62 to supply fluid into or receive fluid from a retract chamber 64 provided between the housing 48 and an outer portion of the deployment sleeve 44. Fluid is forced into the retract chamber 64 and exerts a pressure on an upper surface of a deployment sleeve piston 66 provided at a lower end portion of the deployment sleeve 44, thus causing downwards movement of the deployment sleeve 44 in order to retract the sealing apparatus 14. Conversely, removing fluid from the retract chamber 64 may move the deployment sleeve 44 so as to move the sealing element 20 to the intermediate position.

In order to move the deployment sleeve 44 so as to deploy the sealing apparatus 14, there is provided a deploy port 68 to supply fluid into or receive fluid from a deploy chamber 70 provided between the housing 48 and an outer portion of the pocket isolation sleeve 46. Fluid is forced into the deploy chamber 70 and exerts a pressure on a lower surface of the deployment sleeve piston 66, thus causing upwards movement of the deployment sleeve 44 in order to deploy the sealing apparatus 14. It will be understood that a differential pressure between the retract chamber 64 and deploy chamber 70 may cause movement of the deployment sleeve piston 66. Thus, fluid may be appropriately supplied or removed from either chamber 64, 70 to effectuate appropriate movement of the sleeve piston 66.

In order to isolate the well bore 12 using the sealing apparatus 14, the sealing element 20 is firstly moved into the longitudinal orientation of the intermediate position by appropriate movement of the deployment sleeve 44. The sealing apparatus 14 is then axially moved (e.g. upwardly) through the well bore 12 to engage a well isolation apparatus 72 of the sealing device 16 so as to provide the sealing element 20 in the first position. A seal between the sealing element 20 and the sealing device 16 is provided when the deployment sleeve 44 moves the sealing element 20 into engagement with the sealing element seat 21, and then the seal may or may not be assisted by well pressure acting upwardly on the sealing element 20 against the sealing element seat 21.

In order to isolate the side pocket 18, the pocket isolation sleeve 46 is moved upwardly past the sealing element 20 (when in the second position) into sealing engagement with a well isolation seal bore 80 provided adjacent the well isolation apparatus 72. The pocket isolation sleeve 46 includes a well isolation piston 78 provided in an intermediate section of the pocket isolation sleeve 46. The well isolation piston 78 is arranged to apply an axially directed force on the pocket isolation sleeve 46 by virtue of pressure applied within the well isolation chamber 76. Thus, fluid supplied into the well isolation chamber 76 may apply an axial force on the pocket isolation sleeve 46 to sealingly engage the well isolation seal bore 80. The procedure is reversed when isolation of the side pocket 18 with respect to the well bore 12 is no longer required. Each of the chambers 64, 70, 76 may be appropriately sealed (for example using an O-ring (not shown), or the like, between corresponding portions of the sleeves or pistons) to provide effective pressure containment within the chambers 64, 70, 76. It will be appreciated that the deployment sleeve 44 and pocket isolation sleeve 46 can be of any appropriate form. For example, the sleeves 44, 46 can be tubular in form with annular pistons 66, 78.

As illustrated by FIG. 4, the pocket isolation sleeve 46 can be moved (e.g. vertically upwards) past the base 36 and sealing element 20 when the sealing apparatus 14 is in the second position (and thus accommodated in the side pocket 18). Pressure within the side pocket 18 can then be bled off using any appropriate method and the type of sealing element 20 used can be replaced according to the type of equipment utilised. When a different sealing element 20 is required (e.g. when a different shaped recess 32 is required), the apparatus 14 can be provided in the second position, and the side pocket 18 accommodating the sealing element 20 bled of pressure, so that the sealing element 20 can be safely accessed externally via the side pocket 18 and checked, repaired, removed, or replaced as appropriate.

Referring now to FIG. 5, the sealing element 20 is shown as being sealingly engaged with the well isolation apparatus 72. Accordingly, the sealing element 20 is in sealing engagement with the sealing element seat 21. The sealing apparatus 14 may thus be considered to be in a sealed deployed configuration (i.e. in the first position). In the present example, the well isolation apparatus 72 includes a well isolation ball 82 rotatably mounted in a well isolation body 84. The well isolation ball 82 includes a tapered bore 86 extending axially through the ball 82. In the present example, the tapered bore 86 includes a portion that comprises or defines the sealing element seat 21. The tapered bore 86 may be axially aligned with the axis of the well bore 12 (i.e. when the well isolation ball 82 is in a position to permit access to the well bore 12 through the tapered bore 86). The taper is angled such that the diameter of the bore 86 is smaller at an upper portion of the ball 82 than at a lower portion (i.e. when the bore 86 is axially aligned with the well bore 12). In normal use, equipment (not shown) is locatable through the tapered bore 86 and can be connected to equipment (not shown) downhole of the assembly 10.

A sealing element outer surface portion 88 of the sealing element 20 is also shaped (e.g. tapered, or any other appropriate shape such as a stepped or a flat bottomed seal engagement area in place of the tapered portion) to correspond to the taper of the bore 86. When the sealing element 20 is deployed in the first position, the sealing element 20 is inserted in the bore 86 such that the sealing element outer surface portion 88 sealingly engages a portion of the surface of the tapered bore 86 (e.g. such that the sealing element 20 sealingly engages the sealing element seat 21). If equipment is present in the tapered bore 86, the recess 32 sealingly engages around an external portion of such equipment. Thus, the sealing element 20 may provide a substantially circular well bore seal (if no equipment is present) or a substantially annular well bore seal (if tubular equipment is present). It will be appreciated that other well bore seal shapes may be possible, (e.g., a stepped or a flat bottomed seal engagement area in place of the tapered portion, etc). It is recalled that more than one sealing element 20 may be provided (in the present case there are two sealing elements 20 either side of the well bore 12). Thus the sealing element 20 (or a plurality of appropriately shaped sealing elements 20) may collectively define a plug (for example a frustoconical plug) to seal off the well bore 12 and thus allow depressurisation above the ball 82. Pressure from the well bore 12 itself may increase the axial force applied on the sealing element 20 towards the sealing element seat 21 so as to increase the quality of the seal (and thus enhance well bore 12 isolation). However, when access to the well bore 12 is required (and any pressure differential across the plug has been removed) the sealing apparatus 14 may be returned to the intermediate or second position.

The portion of equipment disposed in the tapered bore 86 may comprises any of wire, pipe, slickline, braided cable, composite cable, micro-coil, coiled tubing, drilling and workover assemblies, and the like. In some examples, such as braided cable, the outer surface of the portion of equipment is uneven and may reduce the quality of any seal created between the sealing element 20 and the outer surface of the portion of equipment. Accordingly, a fluid, such as grease, may be provided on the portion of equipment such that the voids between the portion of equipment and the sealing element 20 and/or voids within the portion of equipment (e.g. between strands of wire) may be filled by the fluid. The fluid may be pumped into the assembly 10 to coat the portion of equipment. In some examples, the inner surface portion 26 of the sealing element 20 may be coated with the fluid such that when the inner surface portion 26 contacts the portion of equipment, the equipment may be coated with the fluid so as to improve the seal.

In some situations it may be necessary to activate an emergency seal (such as in a blow-out situation) to isolate the well bore 12 from surface. In this situation the ball 82 can be rotated by approximately ninety degrees (not shown in the figures) to move the bore 86 into a transverse orientation (i.e. relative to the axis of the well bore 12). Thus, the well bore 12 can be completely or substantially sealed off and permit depressurisation at surface. If equipment is present in the bore 86 of the ball 82, the equipment may be severed by a cutting element 90 provided in the well isolation body 84 as the ball 82 is rotated. The well isolation apparatus 72 may thus function as a BOP.

Various modifications to the apparatus of the assembly 10 are possible. The example of the actuator 30 described herein may be replaced by any appropriate arrangement to move the sealing apparatus 14 between the retracted and deployed configurations. For example, a person of ordinary skill in the art would recognise that the actuator 30 may include a different sleeve arrangement or other appropriate arrangement. At least one sealing element 20 may be provided, for example a single sealing element 20 may be provided in a frustoconical shape. Further, there may be no requirement to provide a guide 34. Only one or some of the sealing elements may include a guide 34. The at least one sealing element 20 may be in the form of any appropriate shape, for example the at least one sealing element 20 may define a cylindrical, hemispherical, conical shape, or the like. Similarly, the corresponding bore of well isolation apparatus 72 may be in any appropriate corresponding shape. In some examples, the well isolation apparatus 72 may not provide any additional functionality other than to allow the sealing apparatus 14 to provide a seal therewith. For example, the well isolation apparatus 72 may not be in the form of a ball 82 and may merely provide a bore 86 to allow the at least one sealing element 20 to be inserted into the bore 86 to seal off the well bore 12. Thus, the sealing apparatus 14 may provide a temporary well bore seal until access is required. In a further example, the pocket isolation sleeve 46 may be locked in place when sealingly engaged with the well isolation seal bore 80 (as illustrated by FIG. 4) so as to effect a positive lock during well isolation and working in the side pocket 18. In a further example, a sealing fluid such as grease may be injected into the assembly 10 so as to improve the seal formed between the sealing element 20 and the sealing element seat 21 and/or the portion of equipment. In a further example, a plurality of cutting elements 90 may be provided, for example, around the well isolation ball 82. A plurality of well isolation balls 82 may be provided in series, each providing backup to the other well bore isolation devices, in case any of the other isolation devices fail or provide inadequate well bore isolation. Any of these examples may be provided separately or may be combined as appropriate. It will be understood that various modifications can be made to any of these examples. 

1-40. (canceled)
 41. Apparatus for isolating a well bore, comprising: a sealing element moveable between a first position, in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore, and a second position, in which the sealing element is axially and transversely displaced from the first position; and an actuator for moving the sealing element between the first and second positions.
 42. The apparatus of claim 41, wherein the sealing element is configured to be inserted into an internal bore defined by the sealing element seat.
 43. The apparatus of claim 42, wherein at least one of: the sealing element is shaped to correspond to the inner surface of the internal bore defined by the sealing element seat; or an outer surface of the sealing element comprises a tapered portion, a stepped portion, or a flat bottomed portion.
 44. The apparatus of claim 41, wherein the sealing element comprises a recess on a surface of the sealing element.
 45. The apparatus of claim 44, wherein the recess is shaped to permit the sealing element to provide sealing engagement with correspondingly shaped equipment when, in use, the equipment is disposed in the internal bore.
 46. The apparatus of claim 41, wherein an intermediate position is defined between the first position and the second position, the intermediate position being axially displaced from the first position.
 47. The apparatus of claim 46, wherein at least one of: the sealing element is pivotable between the intermediate position and the second position; or in the second position, the sealing element is provided in a transverse orientation and is disposed in a side pocket adjacent the bore, and when, in use, the sealing element is in the first or intermediate position, the sealing element is provided in a longitudinal orientation and is disposed in the bore.
 48. The apparatus of claim 41, wherein the actuator comprises at least one sleeve for moving the sealing element between the first and second positions.
 49. The apparatus of claim 48, wherein at least one of: the actuator comprises concentric sleeves configured for moving the sealing element; a first sleeve is axially moveable between a deploy position in which the first sleeve provides the sealing element in one of the first and intermediate positions, and a retract position in which the first sleeve provides the sealing element in the second position; a second sleeve is axially moveable between a sealing element unsealed position in which the sealing element is provided in the second position and in fluid communication with the well bore, and a sealing element sealed position in which the sealing element is in the second position and isolated from the well bore; a retract chamber provided between the first sleeve and a housing for the first and second sleeves, the retract chamber being fillable with fluid so as to apply fluid pressure on a first sleeve piston element provided on the first sleeve; the apparatus comprises a deploy chamber provided between the second sleeve and the housing, the deploy chamber being fillable with fluid so as to apply fluid pressure on the first sleeve piston element provided on the first sleeve and a second sleeve piston element provided on the second sleeve; or a well isolation chamber provided between the second sleeve and the housing, the well isolation chamber being fillable with fluid so as to apply fluid pressure on the second sleeve piston element.
 50. The apparatus of claim 41, comprising a plurality of sealing elements.
 51. The apparatus of claim 41, comprising a guide for locating the sealing element with respect to a portion of equipment when, in use, the equipment is disposed in the bore.
 52. Apparatus for isolating a well bore, comprising: a well bore isolation device comprising a moveable isolation element, the moveable isolation element comprising a sealing element seat, wherein: in a first isolation device position the sealing element seat is axially aligned with a bore and is configured to be sealingly engaged by a sealing element in accordance with claim 41, and in a second isolation device position the moveable isolation element is moved out of axial alignment with the bore.
 53. The apparatus of claim 52, wherein at least one of: the moveable isolation element comprises an internal bore shaped to correspond to an outer surface of the sealing element; the internal bore comprises a tapered portion, a stepped portion, or a flat bottomed portion; the apparatus comprises a cutting element for severing a portion of equipment disposed in the well bore isolation device; or the moveable isolation element comprises a rotatable ball.
 54. An assembly for isolating a well bore, comprising: a sealing element in accordance with claim 41; and a well bore isolation device comprising a moveable isolation element, the moveable isolation element comprising a sealing element seat, wherein: in a first isolation device position the sealing element seat is axially aligned with a bore and is configured to be sealingly engaged by the sealing element, and in a second isolation device position the moveable isolation element is moved out of axial alignment with the bore.
 55. A method of unsealing a well bore, comprising: providing a sealing element in a first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore; and moving the sealing element axially and transversely to a second position in which the sealing element is axially and transversely displaced from the first position.
 56. A method of isolating a well bore, comprising: providing a sealing element in a second position in which the sealing element is axially and transversely displaced from a first position; and moving the sealing element to the first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore.
 57. The method of claim 55, comprising at least one of the following steps: moving the sealing element to the first position by inserting the sealing element in an internal bore defined by the sealing element seat; moving the sealing element between the second position in which the sealing element is axially and transversely displaced from the first position and transversely moving the sealing element to an intermediate position in which the sealing element is axially displaced from the first position; transversely moving the sealing element from the intermediate position to the second position; axially moving the sealing element from the intermediate position to the first position; axially moving the sealing element from the first position to the second position; providing the sealing element in the second position within a side pocket adjacent the bore and isolating the side pocket from the bore; or accessing the sealing element in the side pocket for at least one of: inspection, repair, installation, removal and replacement of the sealing element.
 58. A method of isolating a well bore, comprising: providing a well bore isolation device comprising a moveable isolation element, the moveable isolation element comprising a sealing element seat for providing fluid communication with the well bore; providing the well bore isolation device in a first well isolation device position in which the sealing element seat is in fluid communication with the well bore and is adapted to be sealingly engaged by a sealing element in accordance with claim 41; and moving the well bore isolation device to a second well isolation device position by moving the well bore isolation device to prevent fluid communication with the well bore.
 59. The method of claim 58, wherein at least one of: the moveable isolation element comprises an internal bore shaped to correspond to an outer surface of the sealing element; moving the sealing element from the sealing element seat to unseal the well bore before the well bore isolation device is moved to the second well isolation device position; providing the sealing element in sealing engagement with the sealing element seat such that the sealing element remains sealingly engaged with the sealing element seat, and moving the well bore isolation device to the second well isolation device position; severing a portion of equipment disposed in the well bore isolation device.
 60. A method of isolating a well bore, comprising: providing a sealing element in a first position in which the sealing element is in sealing engagement with a sealing element seat disposed in a bore; providing a well bore isolation device comprising a moveable isolation element, the moveable isolation element comprising a sealing element seat for providing fluid communication with the well bore; positioning the well bore isolation device in a first well isolation device position in which the sealing element seat is in fluid communication with the well bore and is adapted to be sealingly engaged by a sealing element in accordance with claim 41; moving the sealing element axially and transversely to a second position in which the sealing element is axially and transversely displaced from the first position; and moving the well bore isolation device to a second well isolation device position by moving the well bore isolation device to prevent fluid communication with the well bore.
 61. The method of claim 56, comprising at least one of the following steps: moving the sealing element to the first position by inserting the sealing element in an internal bore defined by the sealing element seat; moving the sealing element between the second position in which the sealing element is axially and transversely displaced from the first position and transversely moving the sealing element to an intermediate position in which the sealing element is axially displaced from the first position; transversely moving the sealing element from the intermediate position to the second position; axially moving the sealing element from the intermediate position to the first position; axially moving the sealing element from the first position to the second position; providing the sealing element in the second position within a side pocket adjacent the bore and isolating the side pocket from the bore; or accessing the sealing element in the side pocket for at least one of: inspection, repair, installation, removal and replacement of the sealing element. 